Fig. 12

Overexpression of NMHC II-B reduces TDP-43-mediated neurite toxicity. a Representative immunofluorescent images of TDP-43 (green), NMHC II-B (red), and nuclei (blue) in primary neurons from the mouse cortex, which were transfected with mutant TDP-43 (M337V) and NMHC II-B (+N30) or NMHC II-B (−N30). Note that transfected TDP-43 produced much intense immunostaining signals over the background level in non-transfected cells. Scale bars: 10 μm. b Quantitative data of neurite length of transfected cells. NMHC II-B (+N30) transfection could promote neurite outgrowth and also partly rescue the neurite outgrowth defect caused by mutant TDP-43. The data were obtained by counting more than 300 transfected cells per group in 3 independent experiments. *p < 0.05, **p < 0.01 and ***p < 0.001 compared with TDP-43 transfection alone. GFP: GFP protein; +N30: NMHC II-B (+N30); −N30: NMHC II-B (−N30); WT-TDP-43: wild type TDP-43; MT-TDP-43: mutant TDP-43 (M337V); MT-N30+: mutant TDP-43 (M337V) and NMHC II-B (+N30); MT-N30-: mutant TDP-43 (M337V) and NMHC II-B (−N30). c Proposed model of TDP-43 neuronal toxicity. Because of the interaction of TDP-43 with PSF, the cytoplasmic mislocalization of TDP-43 leads to the cytoplasmic distribution of PSF and NeuN and reduces the nuclear function of PSF and NeuN on the splicing of NMHC II-B, leading to the exclusion of N30, which promotes the degradation of NMHC II-B and affects neuronal function